<!doctype html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>js示例4-6-2</title>
	<script>
		var a;
		a = prompt("请您输入一个年份","");
		if((a % 4 == 0 && a % 100 != 0) || (a % 400 == 0)){
			alert(a + "年是闰年");
		}
	</script>
</head>
<body>
	
</body>
</html>